1. Technical Field
This invention relates generally to automatic gates, and more particularly to a new and improved system for controlling automatic gate operation.
2. Background Information
Motor driven automatic gates often employ a control mechanism that is activated by a gate controller. Operation of the controller by any of various input devices, such as a handheld transmitter unit, sensor loops buried in the roadway, or pushbutton wired to the controller, causes the gate to open and close on command. In this manner, convenient gate operation is accomplished in many applications where it is desired to do so automatically.
However, existing gate controllers suffer from certain drawbacks that need to be overcome. For example, existing controller arrangements often inadequately respond to such contingencies as an obstruction in the path of the gate. In other words, a vehicle or child may be in the way when the gate is operated, and failure to sense this obstruction and alter gate control accordingly may result in significant property damage and personal injury. Thus, this aspect of automatic gate operation is of recognized significance and each detail of gate control is of corresponding importance.
Specifically, an obstruction occurring while the gate is closing is typically caused by different events than an obstruction while the gate is opening, and different control responses are of value in avoiding damage or injury. Although existing gate controllers are able to distinguish between obstructions on opening and obstructions on closing, and are therefore able to take different types of action in response to these different kinds of obstructions, those actions are generally limited to reopening the gate on a closing obstruction, and to stopping it on an opening obstruction.
Another drawback of existing controllers is that the conventional solenoid-operated locking finger or bar which prevents the unintentional moving of the gate by locking the gate's drive train is engaged and disengaged simultaneously with the stopping and starting of the motor. Because the gate has some inertia, this simultaneous engagement creates stresses on the drive mechanism which are prone to result in maintenance problems.
Finally, gate sizes constructions, and locations differ, as well as the type of obstruction, and existing controllers that sense obstructions by monitoring gate speed often require modification or time consuming, periodic adjustment to accommodate the corresponding differences in normal gate speed, and the amount of variance anticipated.
Consequently, it is desirable to have a new and improved controller that overcomes these concerns--one responsive to obstructions in a manner designed to better inhibit damage or injury to the obstruction as well as to the gate mechanism, and one better able to accommodate different types of gates and different types of obstructions.